JP6854898B2 - Manufacturing method of color filter, display device and color filter - Google Patents

Description

The present invention relates to a color filter, a display device including the color filter, and a method for manufacturing the color filter of the present invention.

A color filter is an optical filter that displays colors, and when a light source passes through a color module, the corresponding colors can be displayed accurately, and rich colors can be displayed.

Color filter applications include monochrome displays (eg, VF (Vacuum Fluorescent Display), EL (Electroluminescence Display), by selecting the band path and maximum output of the display (eg, LCD, liquid crystal display). ), LED (light emitting diode display), etc.) may be enhanced in contrast. Broadband filters are used to improve the contrast and performance of optical scanners and red / yellow / amber light emitting diode displays. Medium density 3-slot filters and polarizing mirrors improve the contrast of a liquid crystal display (LCD) by reducing internal reflections and creating a large variable between the display output and the background.

FIG. 1 shows that a color filter is an important component for colorizing a liquid crystal display (Liquid Crystal Display). The liquid crystal display is an inactive light emitting module, which usually includes a color filter 1, a liquid crystal panel 2, a TFT matrix 3, and a backlight module 4, and the internal backlight module is required to display the colors. A light source must be provided by (eg, a transmissive LCD) or external ambient light (eg, a reflective or transflective LCD), and with a driver IC (Drive IC, driver chip) and a liquid crystal panel 2. After forming a gradation display (Gray Scale) by controlling them together, each color layer of the color filters R, G, and B (where R represents red, G represents green, and B represents blue) is displayed. The color is given through the color display screen, and finally the color display screen is formed.

In recent years, it is common to change the structure of a color filter in order to increase the brightness of a panel, but a technique called RGBW as shown in FIG. 2 as a schematic diagram has also been developed.

The technology called RGBW is mainly as follows. In the original display screen, one pixel corresponds to three sub-pixels, that is, one independent pixel corresponds to three RGB sub-pixels. RGBW means that two independent pixels share five sub-pixels by adding one more transparent pixel in addition to the three pixels of R (red), G (green), and B (blue). become. Thus, even at the same resolution, the number of sub-pixels is significantly reduced, thereby reducing costs, increasing transparent sub-pixels, and improving screen brightness. However, one of the disadvantages is that the color optimization is not as good as the original arrangement.

Conventional pixels consist of red (R), green (G), and blue (B), but the pixels of a Full High Definition panel (also referred to simply as an FHD panel) are 1,920 x 1,080. Each pixel consists of three types of sub-pixels. Therefore, the FHD panel has a total of about 6.2 million colors. On the other hand, the resolution of the ultra-high definition panel (Ultra High Definition, also simply called the UHD panel) is 3,840 x 2,160, which means that there are about 24.9 million colors in total. .. Therefore, the resolution of UHD is four times that of FHD panel, and UHD panel is also called 4K panel.

Although the principle is the same, the RGBW panel developed by an ordinary company is slightly different from the conventional UHD TV panel, and the pixels have white (W) sub-pixels added in addition to RGB. is there.

Simply put, the number of pixels per horizontal scanning line of the UHD panel is 3,840, the number of sub-pixels in the RGB layout is 11,520, and the RGBW layout panel has four RGBW subs per pixel. Since it is composed of pixels, the actual number of pixels per horizontal scanning line remains only 2,880. On the other hand, since the number of vertical pixels of the RGBW panel is still 2,160, it is the same as that of the UHD panel arranged in RGB.

As shown in FIG. 1, a conventional pixel is composed of R (red), G (green) and B (blue). The pixels of the FHD panel are 1920 × 1080, and since each pixel is composed of three types of sub-pixels (R, G, B), there are a total of about 6.2 million colors. On the other hand, the resolution of the 4K panel is 3840 x 2160, which means that there are about 24.9 million colors in total (3840 x 2160 types of pixels, each pixel consisting of three types of sub-pixels). Means. Therefore, the resolution of UHD (4K) is four times that of FHD (2K x 1K).

Many companies also employ GMA (color gamut mapping algorithm) and SPR (subpixel rendering) technologies in their RGBW panels to improve image quality. However, the means for adding one such transparent pixel (White Pixel) needs to further increase the number of steps for forming a transparent photoresist. As shown in the manufacturing flowchart of FIG. 3, it is necessary to first wash the glass substrate, apply a black matrix (hereinafter, also simply referred to as BM) photoresist, and form a BM by an exposure development step. Then, a red (R) photoresist is applied, UV exposure is performed through a photomask, and a development step is further performed to form red (R), green (G), and blue (B), respectively. After forming the transparent color (W), an OC flat layer (Over coat, hereinafter simply referred to as OC) is formed on another pixel layer, an ITO (indium tin oxide) plating film is formed on the back surface thereof, and baking is performed. A photoresist spacer (Photo spacer, hereinafter simply referred to as PS) columnar layer (generally including a main columnar layer and a sub-columnar layer) is formed. Due to the addition of the transparent color pixel manufacturing process (including equipment such as lithography / development / curing), the manufacturing cost of the entire color filter is increased by about 12%, which also affects the widespread use of the technology. It ends up.

Patent EP1844462 B1 discloses a conventional RGBW design. The RGBW design proposal disclosed in the patent is a mixture of colors because the W pixel is too far from each of the R, G, and B pixels, as shown in FIG. 4 (FIG. 1 in the patent specification). The effect is not good, the color calculation is not easy, and it is not accurate.

Taking the patent US7515225 as an example, in order to complete the combination of the flat layer and the W pixel in the same process, a BM Layer (black matrix) is created and a columnar layer is also created at the same time. Avoid collapse of the flat layer (OC Layer) at the location of the W pixel. However, the structure has a problem that the light transmittance is lower than that of the original design of RGBW (because the light is blocked by the BM). As shown in FIG. 5, 430 is a color filter pattern, 430a, 430b and 430c are red, green and blue color filter patterns, 420 is a black matrix, and 422 is a virtual pattern, 425a. 425b and 425c represent the first, second and third openings, respectively, 425d represents the fourth opening, 410 represents the substrate, and 440 represents the flat layer.

The above information is used solely for the purpose of deepening the understanding of the background art of the present invention. Therefore, it may contain information that does not constitute prior art known to those skilled in the art.

In view of the above-mentioned existing problems in the RGBW structure, in this field, it can be manufactured by a simple method that does not cause a significant increase in cost, has a good color rendering effect, and has no problem of reducing light transmittance. There is an urgent need to provide a valid RGBW structure given a color filter.

According to the color filter according to the present invention, the light transmittance can be effectively increased without lowering the resolution, and the color mixing effect is good.

According to the color filter according to the present invention, the columnar layer is not distorted, and the finally formed liquid crystal display does not cause the problem of liquid crystal gap unevenness (cell gap mura), which is required by the liquid crystal panel maker. The requirement that the difference between the Cell gaps is less than 0.1 μm can be achieved, and the problem of color unevenness can be effectively overcome.

The present invention also provides a method for manufacturing a color filter. The color filter of the present invention can be efficiently obtained by the manufacturing method. The method is simple to operate, the number of steps involved in the method and the dose of material are the same as those of the conventional manufacturing method, and the manufacturing cost is not significantly increased.

Further, since the transparent pixels are not arranged in an area other than the RGB pixels, not only the light transmittance can be improved, but also the color mixing effect can be enhanced.

The object of the present invention can be achieved by the following technical configuration.

1. 1. With the board
The black matrix formed on the substrate and
A color layer including a red pixel layer, a green pixel layer, a blue pixel layer, and a transparent pixel layer formed on a substrate.
A flat layer formed on the color layer and the black matrix,
A color filter containing a columnar layer formed on a flat layer and on a black matrix.
A color filter in which each red pixel layer, green pixel layer, and blue pixel layer is coated so that the transparent pixel layer is inside the red pixel layer, the green pixel layer, and the blue pixel layer, respectively.

2. Item 1 wherein the columnar layer is composed of a sub-columnar layer and a main columnar layer, and the step between the film thickness heights of each main columnar layer is controlled within a range of ± 0.1 μm, that is, a range of 0.2 μm. Described color filter.

3. 3. Height of transparent pixel layer formed on the substrate (“W height” is also indicated in the present invention) ≤ Height of black matrix formed on the substrate (“BM height” is also indicated in the present invention) Item 3. The color filter according to Item 1 or 2, which satisfies +0.2 μm, that is, A value = W height −BM height ≦ 0.2 μm (where, the value of A may be a negative number).

4. With the board
The black matrix formed on the substrate and
A color layer including a red pixel layer, a green pixel layer, a blue pixel layer, and a transparent pixel layer formed on a substrate.
A color filter containing a columnar layer formed in a black matrix.
Each red pixel layer, green pixel layer, and blue pixel layer is covered so that the transparent pixel layer is inside the red pixel layer, the green pixel layer, and the blue pixel layer, respectively.
A color filter in which a columnar layer is composed of a sub-columnar layer and a main columnar layer, and the step between the film thickness heights of each main columnar layer is controlled within a range of ± 0.1 μm, that is, a range of 0.2 μm.

5. With the board
The black matrix formed on the substrate and
A color layer including a red pixel layer, a green pixel layer, a blue pixel layer, and a transparent pixel layer formed on a substrate.
A color filter containing a columnar layer formed in a black matrix.
Each red pixel layer, green pixel layer, and blue pixel layer is covered so that the transparent pixel layer is inside the red pixel layer, the green pixel layer, and the blue pixel layer, respectively.
Height of transparent pixel layer formed on the substrate (W height) ≤ height of black matrix formed on the substrate (BM height) + 0.2 μm, that is, A value = W height-BM height ≤ 0 .A color filter that fills 2 μm.

6. Item 2. The color filter according to any one of Items 1 to 5, wherein the transparent pixel layer formed on the substrate and coated inside each of the red pixel layer, the green pixel layer, and the blue pixel layer is separated.

7. Item 6. The color filter according to Item 6, wherein the separated transparent pixel layers have a distance of 5 μm or more.

8. Item 2. The color filter according to any one of Items 1 to 7, wherein the substrate is a glass substrate.

9. Item 2. The color filter according to any one of Items 1 to 8, further comprising a conductive layer formed on the back side of the substrate.

10. Item 2. The color filter according to any one of Items 1 to 9, wherein the photoresist material used for each structure forming the color filter is a negative photoresist material.

11. A display panel including the color filter according to any one of Items 1 to 10.

12. Item 11. A display device including the display panel according to Item 11.

13. The process of applying ITO film coating to the back surface of the color filter substrate,
The process of forming a black matrix on the front of the substrate and
The process of forming a transparent pixel layer in the gap between each black matrix formed on the front surface of the substrate, and
A process of coating a transparent pixel layer on a substrate to form a red pixel layer, a green pixel layer, and a blue pixel layer.
A process of forming a flat layer on a red pixel layer, a green pixel layer, a blue pixel layer, and a black matrix, and
A method for manufacturing a color filter, which comprises a step of forming a columnar layer on a flat layer and on a corresponding black matrix.

14. The process of applying ITO film coating to the back surface of the color filter substrate,
The process of forming a black matrix on the front of the substrate and
The process of forming a transparent pixel layer in the gap between each black matrix formed on the front surface of the substrate, and
A process of coating a transparent pixel layer on a substrate to form a red pixel layer, a green pixel layer, and a blue pixel layer.
A method for manufacturing a color filter, which comprises a step of forming a columnar layer on a corresponding black matrix.

15. Item 13. The method according to Item 13 or 14, wherein the height (W height) of the transparent pixel layer formed on the substrate ≤ the height (BM height) of the black matrix formed on the substrate + 0.2 μm.

16. Item 6. The method according to any one of Items 13 to 15, wherein when the transparent pixel layer is formed in the gap between the black matrices, the formed transparent pixel layer is a separated transparent pixel layer.

17. Item 16. The method according to Item 16, wherein the distance between the separated transparent pixel layers is 5 μm or more.

18. Item 6. The method according to any one of Items 13 to 17, wherein the photoresist material used for each structure for forming a color filter is a negative photoresist material.

19. Item 3. The method according to Item 13 or 14, wherein the manufactured color filter is the color filter according to any one of Items 1 to 10.

Based on the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become apparent to those skilled in the art. The drawings herein are for illustration purposes only and are not intended to limit the invention. Obviously, the drawings described below are only a few embodiments of the present invention, and for those skilled in the art, other drawings can be obtained from these drawings without the need for creative effort. In the entire drawing, the same elements are designated by the same reference numerals.

It is a figure which shows the important element for colorization when a color filter is a liquid crystal plane display. It is the schematic which shows the change from RGB to RGBW of a color filter. It is the schematic which shows the manufacturing flow of the conventional RGBW technique. It is a figure which shows one of the RGBW designs in the prior art. It is a figure which shows another RGBW design in the prior art. FIG. 6A is a schematic cross-sectional view showing a problem of the RGBW structure in the prior art, and FIG. 6B is a schematic cross-sectional view showing the RGBW structure of the present invention. It is a figure which shows the process of the manufacturing method of the color filter of this invention. It is the schematic sectional drawing of the color filter structure shown for comparison. It is the schematic which shows the problem of the liquid crystal gap unevenness which occurred in the color filter. FIG. 10A is a schematic cross-sectional view of the color filter structure shown in the examples of the present invention. FIG. 10B is a schematic view showing the relationship between the A value, the step between the RGB layer and the flat layer, and the occurrence of color unevenness of the formed liquid crystal. It is schematic cross-sectional view which shows two embodiments of this invention and the color filter of the prior art. It is the schematic which shows the RGB pixel layer formation process of the color filter of the preferable embodiment of this invention.

Hereinafter, specific examples of the present invention will be described in more detail with reference to the drawings. Although the drawings show specific examples of the present invention, it should be understood that the present invention is not limited to the examples shown below and can be arbitrarily modified and carried out. On the contrary, these examples are provided so that the present invention can be better understood and the scope of the present invention can be fully communicated to those skilled in the art.

In the RGBW structure in the prior art as shown in FIG. 6 (A), as described above, it is necessary to further add a step of manufacturing W transparent pixels in order to obtain the RGBW structure, which increases the manufacturing cost. It is also connected to. Further, the W pixel is far away from the R, G, and B pixels, its color mixing effect is not good, the color calculation is not easy, and it is not accurate. Light transmittance is improved, but resolution is reduced.

FIG. 6B shows a schematic cross-sectional view of the RGBW structure in the present invention. The present invention includes a substrate, a black matrix (represented by BM) formed on the substrate, a red pixel layer (represented by R), and a green pixel layer (represented by G) formed on the substrate. A color layer including a blue pixel layer (represented by B) and a transparent pixel layer (represented by W), a flat layer formed on the color layer and the black matrix (represented by OC), and flat. A color filter including a columnar layer (represented by PS) formed in a layer and located on a black matrix, wherein the transparent pixel layer is inside the red pixel layer, the green pixel layer, and the blue pixel layer, respectively. Provided is a color filter covered with each red pixel layer, green pixel layer and blue pixel layer as described in.

Therefore, as compared with the RGBW structure in the prior art shown in FIGS. 4, 5 and 6 (A), the present invention forms transparent pixels (W pixels) inside the R, G, and B pixels, respectively. , And the difference in forming a flat layer on the color layer. Since the W pixel does not occupy a position, the resolution of the pixel can be improved, the color mixing effect is good, and the process of manufacturing the entire color filter can be simplified.

The color filter of the present invention further includes a conductive layer formed on the back side of the substrate. Here, as the conductive layer, any conductive layer known in the art, preferably an ITO conductive layer may be used.
The substrate of the present invention may be a glass substrate or any other suitable substrate of any kind.
The flat layer of the present invention aims to prevent ion contamination of color (colored) pixels in addition to making the difference in height (step) of R / G / B pixels uniform. Can also be used. This is because the ions cause a change in the driving electrical characteristics of the liquid crystal and further affect the gray gradation (Gray). Further, it is possible to improve the chemical resistance of the pixel layer, the sputter resistance of the conductive film, and the smoothness of the colored pixel layer.

In the present invention, the material for forming the black matrix and each colored pixel layer is not particularly limited, and ordinary materials in the art can be used.

In a specific embodiment of the present invention, the columnar layer is composed of a sub-columnar layer (secondary PS, sub PS) and a main columnar layer (main PS, Main PS), and a step between the film thickness heights of each main columnar layer. Is controlled in the range of ± 0.1 μm, that is, in the 0.2 μm range. By achieving such a structure, the liquid crystal gap in the finally formed liquid crystal screen can be made less than 0.1 μm, and color unevenness does not occur. FIG. 9 shows a schematic view of color unevenness, and it can be seen that gradation unevenness and luminance unevenness may occur after the panel is lit. Here, a person skilled in the art is known as a method for calculating the step between the film thickness heights of each main columnar layer. For example, the film thickness height of the main PS is as high as 90% of the height from the bottom of the PS. It may be the height from the bottom to the top of the main PS. Evaluation may be performed by a calculation method agreed upon by those skilled in the art.

As shown in FIG. 8, if the transparent pixel layer is made too large, the present inventors are likely to cause variation or swelling when the RGB pixels are worn, and the columnar layer (PS) on the flat layer is distorted, resulting in a display. It has been found that there is a problem that liquid crystal gap unevenness occurs as shown in FIG. 9, and further, phenomena such as gradation unevenness and brightness unevenness occur after the panel is lit. Here, if the transparent pixel layer is made too large, as shown in FIG. 8, the height of the transparent pixel layer itself is too high, and the R, G, and B color pixel layers themselves are projected or raised, and R, The G and B pixel layers themselves have a step of more than 0.3 μm.

When the present inventors examined the RGBW structure, the height of the transparent pixel layer formed on the substrate (W height) ≤ the height of the black matrix formed on the substrate (BM height) + 0.2 μm, that is, , A value = W height-BM height ≤ 0.2 μm, it was found that the color unevenness of the liquid crystal screen can be effectively suppressed. 10 (A) and 10 (B) each show a method of calculating the A value, further show the relationship between the A value and the step between the RGB pixel layer and the flat layer, and show the severity of color unevenness in each region. Is also shown.

Further, if the A value is appropriately controlled, the film thickness of the R / G / B colored pixels of the present invention can be controlled more uniformly. In this case, since the flat layer may be omitted, the step of forming the flat layer becomes unnecessary, and the manufacturing cost of the color filter can be further reduced.

That is, the present invention is also formed in a substrate, a black matrix formed on the substrate, a color layer formed on the substrate including a red pixel layer, a green pixel layer, a blue pixel layer, and a transparent pixel layer, and a black matrix. A color filter including a columnar layer, which is formed in each red pixel layer, green pixel layer, and blue pixel layer so that the transparent pixel layer is inside the red pixel layer, the green pixel layer, and the blue pixel layer, respectively. It is coated, and the columnar layer is composed of a sub-columnar layer and a main columnar layer, and the step between the thickness heights of each main columnar layer is controlled within a range of ± 0.1 μm, that is, a range of 0.2 μm. Yes, regarding the color filter.

The present invention is further formed on a substrate, a black matrix formed on the substrate, a color layer formed on the substrate including a red pixel layer, a green pixel layer, a blue pixel layer, and a transparent pixel layer, and a black matrix. A color filter including a columnar layer, wherein each of the red pixel layer, the green pixel layer, and the blue pixel layer is coated so that the transparent pixel layer is inside the red pixel layer, the green pixel layer, and the blue pixel layer, respectively. The height of the transparent pixel layer formed on the substrate (W height) ≤ the height of the black matrix formed on the substrate (BM height) + 0.2 μm, that is, A value = W height-BM height. With respect to a color filter satisfying ≤0.2 μm.

As shown from the cross-sectional structure of FIG. 10A, when A value = W height-BM height ≤ 0.2 μm, the step between the RGB pixel layer and the flat layer is effectively controlled to about 0.1 μm. In this case, the color unevenness does not appear on the display, and the demand of the panel maker can be achieved. Further, in the present invention, since the W pixel is skillfully coated inside the R, G, and B pixel layers, the light transmittance is improved without lowering the resolution, and the color mixing effect is also excellent. Further, the A value may be a negative number, that is, the height of the transparent dye layer may be smaller than the height of the BM.

The present inventors have found that when forming transparent pixels, if continuous strip-shaped transparent pixels are formed, the pixels may be contaminated with each other. In a more preferred embodiment of the invention, the RGBW structure of the invention has been further improved as shown in the bottom figure of FIG. That is, the transparent pixel layer formed on the substrate and coated inside each of the red pixel layer, the green pixel layer, and the blue pixel layer is separated. As shown in the top view on the right side of FIG. 11, in the top view, each transparent pixel layer is not continuous but separated. More preferably, the distance between the separated transparent pixel layers is 5 μm or more.

FIG. 12 shows the merits of such a partition structure. As shown in the upper part of FIG. 12, due to the transparent pixels, for example, the photoresist of the red pixels flows to the adjacent pixels before being molded and fired (baked), which tends to cause an unexpected overlay.

As shown in the lower figure of FIG. 12, since the transparent pixel structure can be separated, the photoresist of the red pixel does not flow to the adjacent pixel before molding and firing (baking). This is because the larger the gap in which the transparent pixels are separated, the more liquid photoresist can be received.

The present invention also relates to a display panel comprising a color filter according to the present invention.
The display panel in the present invention may be, for example, a liquid crystal panel (LCD panel), an organic EL panel (OLED panel), a Micro LED panel, or a reflective panel such as a Micro-cup or a Micro-particle panel.

The present invention also relates to a display device including the display panel of the present invention.

Further, the present invention further comprises a step of coating the back surface of a color filter substrate with an ITO film, a step of forming a black matrix on the front surface of the substrate, and a transparent pixel layer in a gap between each black matrix formed on the front surface of the substrate. The process of forming the red pixel layer, the green pixel layer and the blue pixel layer by coating the transparent pixel layer on the substrate, and the process of forming the red pixel layer, the green pixel layer and the blue pixel layer, and the black matrix. Provided is a method for manufacturing a color filter, which comprises a step of forming a flat layer and a step of forming a columnar layer on the flat layer and on a corresponding black matrix.

The present invention further relates to a process of coating the back surface of a color filter substrate with an ITO film, a step of forming a black matrix on the front surface of the substrate, and a transparent pixel layer in a gap between each black matrix formed on the front surface of the substrate. A color filter including a step of coating a transparent pixel layer on a substrate to form a red pixel layer, a green pixel layer, and a blue pixel layer, and a step of forming a columnar layer on a corresponding black matrix. Providing a manufacturing method for.

Specifically, the method of the present invention includes processing based on a substrate. The commonly used substrate may be, for example, a glass substrate. First, a black photoresist is applied to a glass substrate, and the surface of the glass substrate is covered with the black photoresist. The black photoresist usually uses a negative photoresist material. Unnecessary parts are removed by a process such as exposure development, a black matrix photoresist line is left on the glass substrate, the photoresist line is surrounded by the shape of the matrix, and these rectangular regions are also arranged so that the matrix is aligned.

Next, a transparent photoresist is applied to the gaps between the black matrices formed on the front surface of the substrate, and the transparent photoresist usually uses a negative photoresist. Unnecessary parts of the transparent photoresist are removed by a process such as exposure development to form a transparent color pixel layer that is regularly distributed in the gaps between the black matrices on the substrate. The shape can be changed according to the size (also called resolution) of the pixel aperture area required for different products.

Further, in a more preferable embodiment of the present invention, since the formed transparent pixel layers are separated rather than continuously, the color photoresist in the next step is more easily and uniformly poured into the divided region without accumulating. .. Even after the hot baking process, the irregular structure in which the color pixels are projected does not occur.

Next, a red photoresist is applied to a substrate on which a black matrix and a transparent color pixel layer are formed, and a negative photoresist is usually used as the red photoresist. An unnecessary portion of the red photoresist is removed by a process such as exposure development, and a rectangular region surrounded by the photoresist lines of the black matrix is covered with transparent color pixels to form a regularly distributed red pixel layer. Similarly, the rectangular area surrounded by the photoresist lines of the black matrix is covered with each transparent color pixel to form a plurality of regularly distributed green pixel layers and blue pixel layers at intervals from each other. Here, the red pixel layer, the green pixel layer, and the blue pixel layer each cover the transparent pixel layer and are regularly distributed in the same number at intervals from each other.

Further, the size and spacing of the colored pixels may be set according to the requirements of the pixel size and the resolution. For the setting of the photoresist lines of the colored pixels and the black matrix, a process suitable for the present invention in the prior art can be adopted.

The lithography process used in the present invention obtains a desired pattern on the photoresist layer by steps such as masking, exposure and development based on a photo-chemical reaction mechanism and a chemical / physical etching method, and appears on a glass substrate. Is intended to be.

The photoresist material mainly includes a positive type photoresist and a negative type photoresist. In the positive photoresist, the portion irradiated with light is removed by a chemical substance in the developing process, and the portion not exposed is not taken out by the developer and remains on the glass substrate. On the other hand, in the negative photoresist, on the contrary, the negative photoresist portion irradiated with light is not removed by the chemical product in the developing step, and the portion not irradiated with light is removed by the chemical product in the developing step.

In the production method of the present invention, it is preferable to use a negative photoresist material.

In the production method of the present invention, the color photoresist includes a pigment dispersion, an alkali-soluble resin, a binder resin such as an unsaturated resin monomer, a photopolymerization initiator, an organic solvent, and an additive.

The aromatic group-containing pigment powder in the pigment dispersion is a mixture of a blue pigment and a purple pigment, the blue pigment is one or more of a phthalocyanine pigment, an azo pigment and a heterocyclic pigment, and the purple pigment is a thioindigo pigment. And one or more of diazine pigments. The binder resin is one or more of a polyester acrylate homopolymer, a modified styrene acrylic copolymer, and a yellowing aldehyde-resistant resin resin, and the alkaline or neutral organic solvent is propylene glycol methyl ether acetate or propylene glycol monomethyl ether. , Cyclohexane, propylene glycol diacetate, 2-heptanone and cyclopentanone, and the solvent is n-butanol.

The photopolymerization initiator is one or more of a ketooxime ester-based photopolymerization initiator, a benzyl (benzil) -based photopolymerization initiator, and an alkylphenone-based photopolymerization initiator, and the organic solvent is propylene glycol methyl ether acetate. , Propylene glycol monomethyl ether, cyclohexane, propylene glycol diacetate, 2-heptanone and cyclopentanone, and the additive is a leveling agent, a coupling agent, an antifoaming agent and an ultraviolet absorber. One or more.

FIG. 7 shows a schematic flowchart of the method for manufacturing the color filter of the present invention. For convenience of comparison, a method for manufacturing a color filter having an RGBW structure in the prior art is also shown. As can be seen from FIG. 7, according to the method for manufacturing a color filter of the present invention, transparent pixels can be present inside each colored pixel in advance.

Unlike conventional structural technology (designs other than RGB pixels), transparent pixels are included in the color pixels, so that the effect of improving the light transmittance and the merit of not affecting the color mixing effect can be achieved. In particular, since the transparent pixel has a function of forming an arbitrary irregular structure, it can be changed according to the light transmittance and saturation required for different products, and the color filter of the present invention is used for all energy-saving displays. It will be easier to do.

Table 1 shows the conditions for creating the color filters adopted in the examples and the comparative examples. The PS material having a high film thickness and the photoresist material for forming each of the BM, R, G, B, and W pixels were tested using a material manufactured by JSR Corporation of Japan.
In addition, any of the other commercially available negative photoresist materials can be used in the production of the color filter of the present invention, and the description thereof will be omitted here.

A color filter was manufactured by setting specific parameters as shown in Table 1 according to the above manufacturing method described in the specification of the present application. As shown in FIG. 8, if the transparent pixel layer is made too large, the present inventors are likely to cause variation or swelling when the RGB pixels are worn, and the columnar layer (PS) on the flat layer is distorted, resulting in a display. It has been found that there is a problem that liquid crystal gap unevenness occurs as shown in FIG. 9, and that phenomena such as gradation unevenness and brightness unevenness occur after the panel is lit.

According to the conditions shown in Table 1 above, in Example 1, a series of color filters were obtained by changing the magnitude of the A value. A schematic cross-sectional view of the obtained color filter is shown in FIG. 10 (A). Then, as a result of plotting from the A value and the step, as shown in FIG. 10 (B), when the A value is 0.2 μm or less, the step between the R, G, B layers and the flat layer can be satisfactorily controlled. Further, the step of the columnar layer (PS) above the flat layer, particularly the main columnar layer, is achieved to be in the range of ± 0.1 μm, and the problem of liquid crystal gap unevenness as shown in FIG. 9 occurs in the display. Therefore, the phenomenon of gradation unevenness and brightness unevenness does not occur even after the panel is lit.

In Example 2, it was found that when the transparent pixels are formed, if continuous strip-shaped transparent pixels are formed, the pixels may be contaminated with each other. Therefore, the RGBW structure of the present invention has been further improved. The improved structure has a transparent pixel layer formed on the substrate and coated inside each of the red pixel layer, the green pixel layer, and the blue pixel layer, as shown in the lowermost figure of FIG. It is separated. As shown in the top view on the right side of FIG. 11, in the top view, each transparent pixel layer is not continuous but separated. More preferably, the distance between the separated transparent pixel layers is 5 μm or more. The specific parameters in the manufacturing method are the same as those in Table 1, except that the transparent pixel layer is controlled so as to be separated.

In Example 2, in order to further improve the transparency of the W pixel, the binder resin material which is hard to yellow and has high transparency was used as the resin-based material.

FIG. 12 shows the merits of such a partition structure. As shown in the upper part of FIG. 12, the transparent pixel causes, for example, the photoresist of the red pixel to flow to the adjacent pixel before molding and firing, which tends to cause an unexpected overlay.

As shown in the lower figure of FIG. 12, since the transparent pixel structure can be separated, the photoresist of the red pixel does not flow to the adjacent pixel before molding and firing. This is because the larger the gap in which the transparent pixels are separated, the more liquid photoresist can be received.

This application contains various amendments and substitutable forms. Specific embodiments of the present invention have already been shown in the drawings in combination with examples and are described in detail herein. However, this application is not intended to be limited to the particular form disclosed. Conversely, this application should be construed to include any of the various modifications, equivalents, and substitutable forms without departing from the scope of the invention. The scope of this application is defined by the appended claims and their legal equivalents.

European Patent No. 1844462 U.S. Pat. No. 7,515,225

Claims (6)

With the board
The black matrix formed on the substrate and
A color layer including a red pixel layer, a green pixel layer, a blue pixel layer, and a transparent pixel layer formed on a substrate.
A flat layer formed on the color layer and the black matrix,
A color filter containing a columnar layer formed on a flat layer and located on a black matrix.
Each red pixel layer, green pixel layer, and blue pixel layer is covered so that the transparent pixel layer is inside the red pixel layer, the green pixel layer, and the blue pixel layer , respectively.
The columnar layer is composed of a sub-columnar layer and a main columnar layer, and the step between the film thickness heights of each main columnar layer is controlled within a range of ± 0.1 μm.
The photoresist material used for each structure forming the color filter is a negative photoresist material.
Each of the coated transparent pixel layers is delimited, and there is a gap between the delimited transparent pixel layers.
The distance between the separated transparent pixel layers is 5 μm or more.
Height of transparent pixel layer formed on the substrate (W height) ≤ height of black matrix formed on the substrate (BM height) + 0.2 μm, that is, A value = W height-BM height ≤ 0 .A color filter that fills 2 μm. The color filter according to claim 1, wherein the substrate is a glass substrate, and further includes a conductive layer formed on the back side of the substrate. A display panel comprising the color filter according to claim 1 or 2. A display device including the display panel according to claim 3. The process of applying ITO film coating to the back surface of the color filter substrate,
The process of forming a black matrix on the front of the substrate and
The process of forming a transparent pixel layer in the gap between each black matrix formed on the front surface of the substrate, and
A process of coating a transparent pixel layer on a substrate to form a red pixel layer, a green pixel layer, and a blue pixel layer.
A step of forming a flat layer on any of a red pixel layer, a green pixel layer, a blue pixel layer, and a black matrix, and
A method for manufacturing a color filter, which comprises a step of forming a columnar layer on a flat layer and on a corresponding black matrix, or forming a columnar layer on a corresponding black matrix when there is no flat layer.
The columnar layer is composed of a sub-columnar layer and a main columnar layer, and the step between the film thickness heights of each main columnar layer is controlled within a range of ± 0.1 μm.
The photoresist material used for each structure forming the color filter is a negative photoresist material.
The transparent pixel layer formed on the substrate and coated inside each of the red pixel layer, the green pixel layer, and the blue pixel layer is separated.
A gap is formed between the transparent pixel layers that are separated so that the distance between them is 5 μm or more.
Height of transparent pixel layer formed on the substrate (W height) ≤ height of black matrix formed on the substrate (BM height) + 0.2 μm, that is, A value = W height-BM height ≤ 0 . A method for manufacturing a color filter that satisfies 2 μm. The method according to claim 5, wherein the substrate is a glass substrate, and further includes a conductive layer formed on the back side of the substrate.

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